This invention relates generally to ground water cleaning systems and, more particularly, is directed to a system for removing contaminants from ground water with modified ground water drain wicks.
Of great importance today is the cleaning up of hazardous waste sites. Such sites are often created when hazardous chemicals and the like leak from dump sites at which the hazardous chemicals were deposited or from areas where they were spilled accidentally. As a result, the chemicals seep into the underlying soil and reach the ground water table, thereby contaminating the same.
Conventionally, in order to clean up such hazardous waste sites, the contaminated soil had to be completely removed and then either treated or transported to another site. This has proved to be extremely costly and time-consuming.
More recently, in U.S. Pat. No. 4,582,611 to Wang, it has been suggested to use conventional drain wicks at the contaminated site. In such case, water is injected into a plurality of the drain wicks, and the water and contaminants are removed from the remaining drain wicks, whereupon the removed water and contaminants are supplied to a separate treatment center. However, with this system, the water which leaves the entry wicks (so as to push the contaminants out of the exit wicks), also pushes the polluted or contaminated soil water further out of the contaminated area, thereby increasing the area of contamination and adds to the total volume of water to be treated. Since the cost of treatment of a contaminated site is a function of its area and volume, and since the Wang system increases the volume and area over which the contaminated water is spread, the cost of treatment with this system is increased.
U.S. Pat. No. 4,625,807 to Harlow discloses a method and apparatus for recovery of water-immiscible liquids from water-bearing formations. Harlow is designed to removed hydrocarbons on top of a layer of water, and is only operational with non-miscible pollutants that sit on the surface of a water layer. In other words, Harlow performs a skimming operation, and is particularly applicable to gasoline spills. In Harlow, a container is inserted in the ground. A compressed air line feeds the vessel to purge its interior of accumulated liquid through an exit port on an intermittent basis. Harlow uses check valves with each port and uses a system including a water pump for lowering the water level in the well such that the pollutants on the surface of the water fall into the canister or container for removal.
U.S. Pat. No. 4,625,801 to McLaughlin et al., discloses a method and apparatus for recovering hydrocarbon that accumulates on the underground water tables and is similar to Harlow with the exception that McLaughlin et al., also can remove the water with the hydrocarbon for surface treatment. Both Harlow and McLaughlin et al., require the pumping of water to form a cone of depression and then collect the non-miscible pollutants on top of the water layer and remove the material for treatment at the surface.
U.S. Pat. No. 415,927 to Stiles discloses a hand-operated suction pump that can only raise water from a level of 15-18 feet below the soil's surface. The suction pump is a conventional vacuum pump used in wells. Air is pumped into the water but is only used to aerate the water and merely bubbles through the water in the activated carbon and does not serve to lift the water to the surface.
U.S. Pat. No. 753,780 to Woods discloses a similar arrangement to Stiles and, like Stiles, is intended to be placed in well water away from the soil to obtain potable water. If Stiles or Woods were placed directly in soil, the apparatus thereof would clog up with the soil and be inoperable.
Drain wicks are conventional structures that are used in soil to remove water therefrom. Accordingly, such drain wicks are used to accelerate consolidation of soil and to increase the strength of the soil. Specifically, drain wicks shorten the distance of travel of the water through the soil and provide the water with an easy escape route. Such drain wicks conventionally include a liquid pervious fabric exterior and a solid plastic or corrugated paper core used to retain the shape of the drain wick. Examples of conventional drain wicks are those sold by Burcan Industries, 111 Industrial Drive, Whitby, Ontario, Canada, under the marks "ALIDRAIN" AND "HITEK 8 FLOWDRAIN" and by American Wick Drain Corp., 301 Warehouse Drive, Matthews, N.C., under the mark "AMERDRAIN".